To provide a highly safe damping device of a single-rail carrier by mounting a plurality of light-weighted damping devices which are vital for the single-rail carrier.

The single-rail carrier, which obtains thrust when power is transmitted from an engine and a hole and a rack arranged on a rail are geared with a projection and a pin or the like of a driving wheel provided on a final shaft of a speed reducer, is provided with a brake drum 10 on an intermediate shaft of the reducer of a motive power unit and an intermediate shaft of a speed increasing device of a towing truck, an internal expanding brake 9 for expanding and obtaining braking force by friction force on an inner periphery of the brake drum provided on an inner side of the drum 10, and an other friction brake 11 different from the internal expanding brake 9 for braking by pressing friction material to a whole or a part of a surface on an outer side of the brake drum. A brake structure of the single-rail carrier is so structured that a clutch device for engaging and removing power of the reducer from the engine, the internal expanding brake 9 for operating in synchronization with the clutch device, and the other friction brake 11 different from the internal expanding brake are operated by an other manual lever different from the clutch device.